The use of fiber optic cable as a transmission medium is common in communication systems, including cable television systems. A fiber optic cable is typically a single cable within which is provided a plurality of individual optical fibers. Each optical fiber within the cable may be used to transmit information such as voice or data via light signals.
The proper transmission of light signals is dependent upon the integrity of the cable and the fibers within the cable. Because optical fibers are somewhat delicate and prone to damage, it is imperative that the fibers within the cable be installed and maintained free of any kinks or other damage.
One of the most important parameters of an optical fiber is its "minimum bend radius." The minimum bend radius of the fiber may be different depending upon parameters such as the diameter of the particular fiber. If a fiber is bent beyond its minimum bend radius, the fiber will sustain damage that will degrade its transmission performance. Therefore, it is important that an optical fiber is stored such that it is prevented from being bent beyond its minimum bend radius.
Fiber optic communications systems typically include many interconnections, or "splices," of optical fibers, in which one optical fiber is connected to another optical fiber. Optical fibers are typically stored and spliced in a cabinet-type structure that typically includes a plurality of trays in which excess lengths of different fibers are stored and spliced. Each tray within the cabinet must maintain the integrity of the optical fibers, particularly the minimum bend radius of the fibers, to prevent damage to the fibers stored in the tray.
Typically, the cabinet-type structure consists of a frame containing a plurality of trays for storing the excess cable. Each tray typically stores at least two optical fibers and includes a a "splicing tray" in which the splicing of the optical fibers can be performed by service personnel. Each tray usually includes a fiber entrance for each fiber, a storage area, and a splicing tray. Each tray is typically slidably mounted within the cabinet to allow service personnel to pull each tray outwardly to access to its contents.
There are several existing cabinets for storing and splicing optical fibers in a plurality of trays. U.S. Pat. No. 5,490,229 describes an optical fiber distribution apparatus having a plurality of trays slidably mounted within a frame. Each tray includes a pair of circular drums around which the excess fiber is stored. However, the circular drums undesirably limit the storage area of the tray by defining a fixed path for the stored fiber. Also, there is only a single-stage sliding mount provided on the tray which desirably increases the depth of the tray in order to provide access to the entire tray. Furthermore, the splicing tray is located between the two storage cylinders which does not provide the optimum access to the splicing tray.
U.S. Pat. No. 4,840,449 describes an apparatus for organizing cable splices. This apparatus includes a base plate having two fiber entrances on a single side of the base plate. Fibers are inserted into the tray through each respective entrance and are then wrapped around at least one cylinder extending from the base plate to store the excess fiber. The tray includes a splicing tray spaced from the base plate to permit passage of optical fiber underneath the splicing tray. However, the cylinders extending from the base plate severely limit the storage area of the tray and define only a fixed path for the fiber. Also, the fiber entrances are not located on opposite sides of the tray, thus requiring the cables containing the respective fibers to be run in very close proximity to each other.
Therefore, a need exists for a tray for storing and splicing optical fiber that is easily accessible. A need exists for a tray that does not include fixed cylinders or drums that limit the path for the storage of the fiber. Also, a need exists for a tray that is slidably mounted such that the exposure of the tray is increased such that the entire contents of the tray are accessible without increasing the depth of the tray.